Methods for making polyurea polymer and products prepared therefrom

Abstract

Methods for making polyurea polymer compositions are provided. The methods involve preparing an amine-terminated first prepolymer by reacting isocyanate compound A with a stoichiometric excess of polyamine. The first prepolymer is reacted with a stoichiometric excess of isocyanate compound B to form an isocyanate-terminated second prepolymer. The second prepolymer is reacted with a chain extender. The polymer compositions can be used in different products and are particularly suitable for making golf balls. For example, the polymer compositions can be used to make golf ball covers.

We claim: 
     
       1. A method of forming a golf ball comprising a core of at least one layer and cover of at least one layer, the cover being formed from a polyurea composition, the composition being prepared by a reaction comprising the steps of:
 i) forming an amine-terminated first prepolymer by reacting isocyanate compound A with a stoichiometric excess of polyamine compound; 
 ii) forming an isocyanate-terminated second prepolymer by reacting the first prepolymer with a stoichiometric excess of isocyanate compound B; and 
 iii) reacting the second prepolymer with an amine-terminated chain extender, wherein isocyanate compound A is 4,4′-diisocyanatodicyclohexylmethane diisocyanate (H 12 MDI) and isocyanate compound B is 1,6-hexamethylene diisocyanate (HDI) oligomer. 
 
     
     
       2. A method of forming a golf ball comprising a core of at least one layer and cover of at least one layer, the cover being formed from a polyurea composition, the composition being prepared by a reaction comprising the steps of:
 i) forming an amine-terminated first prepolymer by reacting isocyanate compound A with a stoichiometric excess of polyamine compound; 
 ii) forming an isocyanate-terminated second prepolymer by reacting the first prepolymer with a stoichiometric excess of isocyanate compound B; and 
 iii) reacting the second prepolymer with an amine-terminated chain extender, wherein isocyanate compound A is 2,4-toluene diisocyanate (TDI) and isocyanate compound B is 4,4′-diphenylmethane diisocyanate (MDI). 
 
     
     
       3. The method of  claim 1 , wherein the polyamine compound is selected from the group consisting of amine-terminated hydrocarbons, polyethers, polyesters, polycarbonates, polycaprolactones, and mixtures thereof. 
     
     
       4. The method of  claim 1 , wherein the polyamine compound is an amine-terminated copolymer of polytetramethylene oxide and propylene oxide. 
     
     
       5. The method of  claim 1 , wherein the chain extender is an amine-terminated chain extender selected from the group consisting of 4,4′-diamino-diphenylmethane; 3,5-diethyl-(2,4- or 2,6-) toluenediamine; 3,5-dimethylthio-(2,4- or 2,6-)toluenediamine; 3,5-diethylthio-(2,4- or 2,6-) toluenediamine: 2,2′-dichloro-3,3′,5,5′-tetraethyl-4,4′-diamino-diphenylmethane; polytetramethyleneglycol-di(p-aminobenzoate); 4,4′-bis(sec-butylamino)-dicyclohexylmethane; and mixtures thereof. 
     
     
       6. The method of  claim 5 , wherein the amine-terminated chain extender is dimethylthiotoluenediamine. 
     
     
       7. The method of  claim 5 , wherein the amine-terminated chain extender is diethyltoluenediamine. 
     
     
       8. The method of  claim 1 , wherein the first prepolymer contains 0.1 to 20 weight percent unreacted amine groups. 
     
     
       9. The method of  claim 1 , wherein the second prepolymer contains 0.1 to 15 weight percent unreacted isocyanate groups. 
     
     
       10. The method of  claim 1 , wherein the isocyanate-terminated second prepolymer and amine chain extender are reacted so that the stoichiometric ratio of isocyanate to amine groups is in the range of about 0.95:1.00 to about 1.10:1.00. 
     
     
       11. The method of  claim 1 , wherein the core comprises polybutadiene rubber. 
     
     
       12. The method of  claim 1 , wherein the core is a dual-layered core. 
     
     
       13. The method of  claim 1 , wherein the cover is dual-layered cover. 
     
     
       14. The method of  claim 1 , wherein the golf ball further comprises an intermediate layer disposed between the core and cover. 
     
     
       15. The method of  claim 14 , wherein the core has a diameter of about 1.26 to about 1.60 inches and surface hardness in the range of about 30 to about 65 Shore D. 
     
     
       16. The method of  claim 14 , wherein the intermediate layer has a thickness of about 0.015 to about 0.120 inches and surface hardness in the range of about 45 to about 75 Shore D. 
     
     
       17. The method of  claim 14 , wherein the cover layer has a thickness of about 0.015 to about 0.090 inches and material hardness in the range of about 40 to about 65 Shore D.